They are the first to be charged under an international law-enforcement operation that targets U.S. citizens who travel to Cambodia for illicit sex. They could face 30 years in jail for each victim.

Three American men who are suspected of traveling to Cambodia to molest children have been charged in federal court as part of a new initiative aimed at cracking down on the child sex tourism business there, authorities said Monday.

Ronald Gerard Boyajian, 49, of Menlo Park, Calif.; Erik Leonardus Peeters, 41, of Norwalk; and Jack Louis Sporich, 75, formerly of Santa Monica and currently living in Sedona, Ariz., were arrested by Cambodian police in February, authorities said. They were recently expelled from the country and arrived Monday at LAX in the custody of U.S. immigration officials.

The three men, all previously convicted of sex offenses in the United States, were charged here in absentia earlier this year with traveling overseas for the purpose of engaging in illicit sexual conduct with minors, a charge that could bring up to 30 years per victim, authorities said.

They are the first to be charged under an international law-enforcement operation dubbed "Twisted Traveler," specifically targeting American sex offenders who travel to Cambodia, a country that one U.S. immigration official said was "the world's ground zero for child sex tourists."

"These types of cases are disturbing not only because young, defenseless children were victimized in unspeakable ways," U.S. Atty. Thomas O'Brien said at a news conference Monday. "But also because the defendants went to such lengths to engage in their dark activities overseas."

Although they were also charged in Cambodia for their alleged crimes, O'Brien said the sentences they face in the U.S. if convicted are "severely stronger."

Boyajian is suspected of traveling to Cambodia a year ago and molesting a 10-year-old Vietnamese girl, according to court papers. Peeters is accused of sexually abusing at least three Cambodian boys whom he paid between $5 and $10, according to a court affidavit.

And Sporich is suspected of molesting at least one underage Cambodian boy after he arrived in November 2008, according to the affidavit. Authorities said he would drive his motor bike through city streets and drop money as a way to lure children.

Americans have been arrested in the past for having illicit sexual contact with minors in foreign countries. But under this new initiative, the focus is on Cambodia, and FBI and immigration officials are training foreign nationals in evidence gathering, surveillance and victim interviews, O'Brien said. Their goal is to obtain evidence admissible in a U.S. court, he said.

"We are committed to the difficult but necessary task of ending this scourge, despite cost, despite distance, despite international boundaries," said John Morton, assistant secretary for Immigration and Customs Enforcement. "There can be no place for the abuse of foreign children by U.S. citizens."